<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>shader</title>
    <style>
        shader-doodle {
            position: absolute;
            width: 100%;
            height: 100%;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }
    </style>
</head>
<body>
    <script src="https://unpkg.com/shader-doodle@alpha"></script>
    <shader-doodle>
    <script type="x-shader/x-fragment">
        void main() {
            gl_FragColor = vec4(vec3(1, 0.5, 1), 1.0);
        }
    </script>
    </shader-doodle>
</body>
</html>